Just when we thought life was getting back to normal, Covid rates are climbing again.
Latest figures showed that 345 of the UK’s 377 local areas have seen a rise in infections, with fresh warnings of increased pressure on the NHS.
But how can so many people be catching Covid with so many people double vaccinated? And should we be worried that we might be facing another tough winter at the mercy of the virus?
Here Azeem Majeed, professor of public health at Imperial College London, explains what’s happening…
What is a breakthrough infection?
No vaccine is 100% effective against preventing infection.
AFP via Getty Images)
An infection in a fully vaccinated person is sometimes described as a breakthrough infection because the infective agent has “broken through” the protection from infection provided by the vaccine.
How common is Covid-19 infection in fully vaccinated people?
Data from Public Health England show that the Covid-19 vaccines used in the UK reduce the risk of infection by about 70-90% in people who are fully vaccinated, so vaccines prevent the majority of people who are vaccinated from becoming infected.
However, some people who are fully vaccinated will still become infected.
It is also possible that the immunity from infection from vaccination will weaken over time, with breakthrough infections therefore becoming more common, which is why the government is now considering giving booster doses of vaccine to some people.
How serious is Covid-19 infection in vaccinated people?
Research shows that vaccines are very effective in reducing the risk of serious illness from a Covid-19 infection, with around a 95% reduction in the risk of hospitalisation and death.
However, some people who are vaccinated will still have a serious illness. As with infections in unvaccinated people, the risk of a serious illness is highest in the elderly and people with medical problems such as diabetes and obesity.
What makes a breakthrough infection more likely?
The more people you come into close contact with, the more likely you are to have a breakthrough infection.
People whose work involves a lot of contact with other people, such as health professionals, will be at greater risk of a breakthrough infection.
The risk of a breakthrough infection is also higher in people with weak immune systems because vaccines work less well for them.
The risk of becoming infected with Covid-19 is highest in poorly-ventilated, crowded indoor spaces. To reduce your risk of infection, you should as far as possible, avoid these kinds of settings. A face mask can provide some protection from infection, particularly if you use a higher specification mask such as FFP2 mask.
How do new variants like delta effect the risk of infection?
The delta variant of the coronavirus that spread across the world in 2021, and which is now responsible for nearly all cases of Covid-19 in the UK, is more infectious than other variants.
Vaccines will be a little less effective at preventing infection from the delta variant than the variants that were previously circulating in the UK.
However, vaccines still remain very effective at preventing serious illness, hospitalisation and death, even against infections caused by the delta variant. So far, we have not yet come across a variant of the coronavirus against which vaccines are ineffective.
How well are vaccines working in the UK?
Very well. Around 81% of people aged 16 and over have been fully vaccinated. Public Health England estimates that around 24 million infections, 144,000 hospitalisations and 112,000 deaths have been prevented by vaccination.
Without vaccines, the number of cases, hospitalisations and deaths in the UK would be much higher than now, requiring further Covid-19 restrictions and lockdowns to control the pandemic.
It is vaccines that have allowed the government to relax these restrictions and let people to live more normally.
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